Top 20 drug - drug interactions, polypharmacy and analysis of the nature of risk factors due to QT interval prolonging drug use in elderly psychiatry outpatients.

INTRODUCTION AND OBJECTIVES

Psychotropic medications extend the corrected QT (QTc) period in the ECG. Psychiatric patients exposed to ≥ 1 psychotropic medication (s) represent a group with a marked probability of drug-activated QTc-prolongation. Prolonged QTc interval in elderly patients (age > 60 years) is connected to a greater risk of all-cause and coronary heart disease deaths. We investigated the pattern of utilization of QTc-interval prolonging medications, QT-extending interactions between drugs, and prevalence of QTc-interval prolonging risk factors in elderly patients.

METHODS

This was a cross-sectional, prospective study at the Psychiatry OPD at All India Institute of Medical Sciences (AIIMS), Rishikesh, Uttarakhand, India from October 1, 2017 to December 31, 2018 employing the pertinent prescriptions.

RESULTS

A total of 208 elderly patients (age 60 years or more) visiting the Psychiatry OPD during the aforementioned study period were investigated. 105 (50.5%) patients were males whereas 103 (49.5%) were females in our study. 147 out of 208 patients (70.7%) were using interacting agents with the capacity to produce TdP. 288 interacting torsadogenic medication pairs were unraveled. As per AzCERT/CredibleMeds Classification, 254 (48.8%), 181 (34.8%), and 62 (12%) interacting medications were identified with known, possible, and conditional risk of TdP, respectively. The common interacting medications belonged to antidepressant (144), proton pump inhibitor (91), antipsychotic (85), anti-nausea (46), antimicrobial (39), and H receptor antagonist (15) therapeutic categories.

CONCLUSIONS

Many geriatric patients were administered drugs and drug combinations with heightened proclivity towards QT-interval prolongation. Therefore, we need to exigently embrace precautionary safety interventions, to be vigilant, and forestall QT-prolongation and TdP in clinical settings. Online evidence-based drug information resources can aid clinicians in choosing drugs for psychiatric patients.